16.2 Reagent and Procedure Quality Assurance

16.2 Reagent and Procedure Quality Assurance

Quick Answer: QC ABO sera, anti-D, reverse cells, and AHG each day of use. Look at the vial — hemolysis, turbidity, precipitate, or a color change takes the bottle out of service. Parallel-test new lots against the current lot before patients see them. Monitor refrigerators (1–6 °C), freezers, 37 °C incubators, and 20–24 °C platelet incubators. Calibrate centrifuge timer, speed, and function. Check cell-washer residual saline. Do not release results after a QC failure until the failure is investigated. Immunohematology is CLIA high-complexity: written SOPs, competency, and proficiency testing.

The June 9, 2026 outline puts reagent and test-procedure QA next to sample QA under IV.D. Chapter 15 told you what is in the bottle. This section is the morning proof that the bottle, the serofuge, and the person at the bench are still allowed to report a type.

Daily reagent QC and visual inspection

Each day of use, control:

• Anti-A, anti-B (and anti-A,B if you use it) against known A, B, and O cells so you see the positive and negative reactions the SOP names.
• Anti-D against known D-positive and D-negative cells. High-protein reagents still need their Rh control to be nonreactive.
• Reverse grouping cells (A1 and B) against known group A, B, and O plasma or the equivalent QC material.
• AHG with IgG-coated cells (and a negative control as required). In tube systems, the check-cell lot plus a documented negative often satisfies the AHG check — but check cells still go only into negative patient AHG tubes (Chapter 15).

Visual inspection is QC. A hemolyzed screening-cell vial, a cloudy AHG, a precipitated monoclonal, a frozen bottle that should have stayed liquid, or a reagent past the labeled expiration is out of service even if yesterday’s worksheet was perfect. Record the inspection. “It looked fine” is not a result.

New lots and new shipments are parallel-tested with the current acceptable lot (or with well-characterized cells/sera) before they replace the working set. A new lot of anti-D that is weaker than the old lot on a known weak-D cell is not “close enough.” Record lot numbers, expiration, and the parallel results. Do not mix leftover old-lot and new-lot drops in the same well.

Temperature, centrifuges, and cell washers

Reagent and specimen refrigerators are 1–6 °C with continuous monitoring and an alarm. Component freezers follow the product (commonly −18 °C or colder for frozen plasma; colder still for frozen red cells). Platelet incubators are 20–24 °C with continuous agitation. Heat blocks and water baths used for 37 °C IAT are checked on a defined schedule; a “37 °C” block that is actually 32 °C misses warm antibodies. Chart recorders, digital probes, and daily staff checks are complementary, not interchangeable. A gap in the temperature record is a QC event, not a paperwork nuisance.

Centrifuge calibration is three jobs, not one sticker:

1. Timer — the serofuge actually spins for the seconds the SOP names.
2. Speed / RCF — a tachometer or calibrated stroboscope confirms RPM; convert to the RCF the insert requires.
3. Function — a known weak 1+ button still looks like 1+, and a true negative still resuspends. Overspin makes everything look positive; underspin hides weak ABO reverse reactions.

Cell-washer efficiency is about what is left after the last wash. Residual saline dilutes AHG. Residual serum globulin neutralizes AHG and produces false-negative IAT/DAT results that then fail check cells — or, worse, pass check cells if the washer left a thin film you did not notice. Periodic checks use a protein or volume method the SOP names. A washer that leaves pink, protein-rich supernatant is not “good enough for STAT tubes.”

Procedures, proficiency, competency, CLIA

Immunohematology — ABO/Rh, antibody detection and identification, compatibility testing, DAT — is CLIA high-complexity testing. That classification drives personnel qualifications, a technical supervisor, written procedures, and proficiency testing. It is not waived work you can assign to untrained staff on a holiday weekend.

SOPs define specimen requirements, reagent QC, grading, interpretation, computer entry, and the critical steps you may not skip: two identifiers, historical type check, QC before patients, check cells in negative AHG tubes, and the discrepancy hold. Deviations are documented, not improvised. If the SOP says wash four times, you do not wash twice because the OR is calling.

Proficiency testing (PT) uses CMS-approved events (commonly CAP surveys). Graded events are scored against the peer/referee result; an unsuccessful event requires investigation, corrective action, and sometimes cease-testing for that analyte until competency is restored. Ungraded / educational challenges are not scored but are still worked as unknowns and reviewed. Treat PT samples like patients: same method, same computer path. Do not refer the challenge to another laboratory or discuss answers across sites — that is a CLIA prohibition, not a courtesy.

Competency assessment for testing personnel is required at 6 months after hire (or after a new method) and at least annually thereafter. CLIA’s six elements include direct observation, recording/reporting review, worksheet review, PT or unknown-sample testing, problem-solving, and (as applicable) maintenance. A signature on an SOP roster is not competency.

QC failures and the release rule

Investigate QC failures before releasing results. If anti-B QC is unexpectedly negative, you do not finish the morning type-and-screen batch and “footnote” the QC later. Stop. Repeat QC with fresh cells or a new vial. If QC then passes and you can show the patient tests were not yet started, proceed. If patient tests already ran under failed QC, repeat them under passing QC or document a validated exception that the medical director accepts. The same rule applies to a failed temperature chart, an out-of-calibration serofuge, and a cell washer that left protein in the tubes.

Worked scenario. Monday AHG QC with IgG-coated cells is nonreactive. Check cells added to that QC tube are also nonreactive. Do not report overnight DATs. Open a new AHG vial, repeat QC, review whether last night’s washer left residual saline, and repeat any negative AHG tests that were read under the failed reagent. A neutralized or omitted AHG is how a real warm auto or a delayed Kidd DAT is called negative.

Exam traps

• Skipping daily ABO/AHG QC because “we ran it yesterday and the bottles are still cold.”
• Putting a new lot into service without parallel testing.
• Releasing a batch after failed QC and investigating after lunch.
• Calling a temperature-chart gap acceptable because the door was “probably shut.”
• Treating cell-washer residual saline as cosmetic rather than an AHG-neutralization risk.
• Discussing PT answers with another hospital.
• Equating a signed SOP with competency.